1. Field of the Invention
The present invention relates to methods of using polyvinyl alcohol based fabrics. In particular, the present invention includes methods for oil, wax, or hydrocarbon solvent absorption or adsorption and release using textiles formed from polyvinyl alcohol based fibers.
2. Background of the Invention
The spillage of oil or oily substances such as waxes is a common occurrence. In the household setting, such spills are generally cleaned using a fibrous material such as a paper towel or a cotton towel. The recovery of oil or wax by cotton towels is adequate at best. Moreover, once used, it is difficult to remove the oils from the cotton fabric for reuse of the fabric.
In the industrial setting, special non-woven fabrics have been developed to assist in the recovery of oils or waxes. These non-wovens perform better than cotton fibers at absorbing oil. An example of such a non-woven is the 3M(copyright) SRP Petro Spill Response Pack (3M Company, Minneapolis, Minn.) product. However, this product is expensive and does not release the oil or wax sufficiently rapidly to be practical. Therefore, there exists a need for reclamation and recovery methods employing superior materials.
In addition, where large oil spills have contaminated sand, there exists a need for a more effective way to recover oils or oily substances from the sand.
Moreover, once the typical fabrics become saturated with oil or wax, they must be disposed of, which is an added expense.
Therefore there exists a need for a novel method of recovering and releasing oil or oily substances such as waxes. In addition, there exists a need for novel methods of recovering oil or wax from oil/sand mixtures. Finally, there exists a need for efficiently disposing of used recovery materials after the oil or wax has been recovered.
The present invention is capable of solving these drawbacks and can provide further surprising properties.
The present invention includes a method of absorbing or adsorbing oil or wax comprising contacting the oil or wax with a non-woven, woven, or knitted fabric prepared from a hot water soluble, cold water insoluble polyvinyl alcohol fiber.
In another embodiment, the invention includes a method of recovering oil or wax contained in a non-woven, woven, or knitted fabric, comprising contacting the fabric with water wherein the woven fabric is formed from polyvinyl alcohol fiber formed from a hot water soluble, cold water insoluble polyvinyl alcohol fiber.
In a further embodiment, the present invention includes a method of disposing of a non-woven, woven, or knitted fabric prepared from a hot water soluble or dispersible, cold water insoluble or nondispersible polyvinyl alcohol fiber, comprising the steps of:
a) absorbing or adsorbing an oil or wax onto the fabric; and
b) contacting the fabric with water of a sufficient temperature and for a sufficient period of time to dissolve or disperse the fabric.
In yet another embodiment, the invention includes a method of absorbing or adsorbing an aliphatic or aromatic hydrocarbon solvent comprising contacting the hydrocarbon solvent with a nonwoven or woven fabric prepared from a hot water soluble, cold water insoluble polyvinyl alcohol fiber.
Additional advantages that can be associated with the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the appended claims. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed.
The present invention may be understood more readily by reference to the following detailed description of preferred embodiments of the invention.
Before the present articles and methods are disclosed and described, it is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. It must be noted that, as used in the specification and the appended claims, the singular forms xe2x80x9caxe2x80x9d, xe2x80x9canxe2x80x9d and xe2x80x9cthexe2x80x9d include plural referents unless the context clearly dictates otherwise.
Throughout this application, where publications are referenced, the disclosures of these publications in their entireties are hereby incorporated by reference into this application in order to more fully describe the state of the art to which this invention pertains.
The present invention includes a method of absorbing or adsorbing oil or wax comprising contacting the oil or wax with a non-woven, woven, or knitted fabric prepared from a hot water soluble, cold water insoluble polyvinyl alcohol fiber.
By xe2x80x9chot waterxe2x80x9d it is intended to refer to water at or above 37xc2x0 C., more preferably above 50xc2x0 C., even more preferably above 75xc2x0 C., and still more preferably above 90xc2x0 C. By xe2x80x9ccold waterxe2x80x9d it is intended to refer to water below 37xc2x0 C.
The PVA fibers suitable for this invention include those disclosed and described in U.S. Pat. Nos. B1 5,181,966 and B1 5,207,837, the contents of both of which are incorporated herein in their entirety by this reference. For example, suitable fibers included polyvinyl alcohol fibers comprising polyvinyl alcohols with or without acetyl groups, cross-linked or uncross-linked. An example of a suitable polyvinyl alcohol fiber for use in the present invention is a polyvinyl alcohol homopolymer that has been highly crystalized by post drawing or by heat annealing.
In one embodiment, a non-woven fabric can be formed from spun-bonded polyvinyl alcohol fibers. Alternatively, the non-woven fabric can be formed by melt blowing the polyvinyl alcohol fibers. In still a further embodiment, the non-woven fabric can be formed by dry carding and hydroentangling the polyvinyl alcohol fiber. In another embodiment, the non-woven fabric can be formed by thermally bonding the fiber. In addition, the fabric can be formed by dry laying the fiber. In yet another embodiment, after dry laying, the fiber can be carded to produce a more uniform distribution of fibers and then needle-punched to enhance the strength of the fabric. Finally, after carding and needle-punching, the fiber can, optionally, be thermobonded. In still a further embodiment, the non-woven fabric can be formed by chemical bonding the fiber.
In still a further embodiment, the fabric can be formed from woven polyvinyl alcohol fibers. In yet another embodiment, the fabric can be formed from knitted polyvinyl alcohol fibers. To this end, any known technique for knitting and/or weaving fibers can be employed.
The methods of the present invention can be employed with a variety of oils and waxes. For example, the oil or wax can be a mineral oil. Alternatively, the oil can be a vegetable-derived oil such as, but not limited to, corn oil. In fact, the oil can be an engine oil. Other examples of suitable oils and waxes include crude oil and its refined products such as gasoline, kerosene, diesel oil, fuel gas, heating oil, furnace oil, asphalt, black fuel oil, and coke.
The present invention also includes a method of disposing of a non-woven, woven, or knitted fabric prepared from a hot water soluble, cold water insoluble (or nondispersible) polyvinyl alcohol fiber. The disposal method includes the steps of first absorbing or adsorbing oil or wax onto the fabric. The oil or wax need not saturate the fabric. Next, the method involves contacting the fabric with water of a sufficient temperature and for a sufficient period of time to dissolve or disperse the fabric. Thus, by using this disposal method, there is no solid waste fabric product to dispose of and the solution of oil or wax and dissolved fabric can be readily disposed of.
The present invention further includes a method of recovering oil or wax contained in a non-woven, woven, or knitted fabric, comprising contacting the non-woven, woven, or knitted fabric with water and agitating the fabric and/or water, where the non-woven, woven, or knitted fabric is formed from polyvinyl alcohol fibers. In one embodiment, the water is at room temperature.
In another embodiment, the present invention includes a method of absorbing or adsorbing oil or wax from a mixture comprising an oil or wax and sand (such as oil-contaminated sea sand) or gravel comprising contacting the mixture with a non-woven, woven, or knitted fabric, where the non-woven, woven, or knitted fabric is comprised of polyvinyl alcohol fibers.
In yet another embodiment, the invention provides a method of absorbing or adsorbing an aliphatic or aromatic hydrocarbon solvent comprising contacting the hydrocarbon solvent with a non-woven, woven, or knitted fabric prepared from a hot water soluble, cold water insoluble polyvinyl alcohol fiber.
The following examples are set forth so as to provide those of ordinary skill in the art with a complete disclosure and description of how the compositions and articles claimed herein are made and evaluated, and are intended to be purely exemplary of the invention and are not intended to limit the scope of what the inventors regard as their invention. Efforts have been made to ensure accuracy with respect to numbers (e.g., amounts, temperature, etc.) but some errors and deviations should be accounted for. Unless indicated otherwise, parts are parts by weight, temperature is in xc2x0C. and is at room temperature, and pressure is at or near atmospheric.
The examples demonstrate the ability to provide the following:
1. Both PVA woven and non-wovens can absorb oil. While the woven is similar in performance to cotton, the non-woven is surprisingly absorbent;
2. In water, the PVA woven towel released absorbed oil at a much faster rate than cotton;
3. At room temperature, the PVA woven towel releases a larger amount of oil than cotton; and
4. PVA woven and non-woven fabrics can absorb oil from oil/sand mixtures and the absorbency of the fabrics are dependent on the oil concentration in the sand.
For oil or wax recovery testing, the following protocol was used.
1. 5 ml. of oil was added to 4 g. of towel sample (8 fold);
2. The Towel was soaked in water, under moderate agitation;
3. After 30 minutes, the volume of oil floating on the top of the water was measured and the percentage of recovered oil was calculated.
The cotton towel used was a blue cotton towel (26xe2x80x3xc3x9716xe2x80x3 67 g. Blue Non-Sterilized MedSurg(trademark) Towel, MedSurg, Norcross, Ga.). The PVA fabrics tested were OREX(copyright) Towel-Teal (Isolyser Company Inc., Norcross, Ga.) non-woven fabric 52 g., 25xe2x80x3xc3x9715xe2x80x3 untreated white and OREX(copyright) woven towel, teal colored, untreated.
For absorption testing, the following protocol was followed (using the same towels, as well as using a 3M(copyright) spunbonded non-woven fabric used in 3M(copyright) Petroleum Sorbent kits.
1. Soak pre-weighed fabric samples into oil (10W30 engine oil, Castrol) for 20 minutes;
2. Remove fabric samples from oil and put them in a funnel for 1 hour; and
3. Measure the weight of the oil absorbed in the fabric and calculate the weight ratio of oil to fabric.
The protocol for determine oil release rate (using 10W30 engine oil again) was as follows:
1. Oil saturated fabrics are placed into a weighed cylinder; and
2. Water is added into the cylinder and the amount of oil is measured at various time intervals.
The following protocol was used for testing oil absorption from an oil/sand mixture:
1. Oil (engine oil 10W30) was mixed with sand for 20 minutes;
2. Pre-weighed fabric samples were added to the oil/sand mixture for 20 minutes; and
3. After the 20 minutes, the fabric samples were removed and weighed to determine the weight of oil absorbed in the fabric.